Apparatus for automated cassette handling

Abstract

An automated cassette handler for transporting a cassette containing integrated circuit wafers between first and second elevators in a standardized mechanical interface (SMIF) system for integrated circuit processing. The handler is adapted to grip and transport the cassette while positively pushing the wafers into the cassette.

What is claimed is: 
     
       1. An automated cassette handler for transporting integrated circuit wafers held in a wafer cassette within a canopy, said cassette having at least a closed side and an oppositely directed open side, said canopy coupled to a piece of integrated circuit processing equipment, said handler comprising: a swinger housing within the canopy;   at least two parallel rotation arms coupled between the canopy and the swinger housing so that the swinger housing can be rotationally moved along an arc within the canopy while maintaining the swinger housing in a substantially constant plane with respect to the canopy;   driver means coupled by a shaft to the rotation arms for rotating the swinger housing;   gripper means coupled to the swinger housing for grasping and holding the cassette while the swinger housing is rotated to lift and transport the cassette;   depressor means pivotally coupled to the swinger housing and being swingably mounted for movement in a horizontal plane for retaining the wafers within the cassette by engaging the wafers along said open side of said cassette while the cassette is lifted and transported;   first sensor means coupled to the gripper means for sensing whether the cassette has been gripped by the gripper means;   second sensor means coupled to the depressor means for sensing the position of the depressor means; and   third sensor means coupled to at least one of the rotation arms for sensing the position of the swinger housing.   
     
     
       2. An automated cassette handler as in claim 1 wherein the handler is a module installed in the canopy. 
     
     
       3. An automated cassette handler as in claim 1 wherein the canopy and the piece of processing equipment have first and second guides adapted to engage the lower surface of the wafer cassette, so that the wafer cassette can be removed from the guides only by lifting the wafer cassette along the rotational arc. 
     
     
       4. An automated cassette handler as in claim 1 further comprising: a switch for initiating transport of the cassette; and   controller means coupled to the driver means, the gripper means, the depressor means, the first sensor means, the second sensor means, the third sensor means and the switch for automatically controlling the gripping, lifting, and transporting of wafers retained within the cassette.   
     
     
       5. An automated cassette handler as in claim 1 further comprising; upper and lower pivots to couple each of the rotation arms to the canopy; and   a shaft extending from at least one of said pivots to the exterior of the canopy.   
     
     
       6. An automated cassette handler as in claim 5 wherein the driver means comprises: a motor mounted externally to the canopy; and   a drive linkage coupled between the motor and the shaft.   
     
     
       7. An automated cassette handler as in claim 5 wherein third sensor means comprises: a flag affixed to the shaft; and   an optical sensor for signaling the position of the flag relative to the canopy.   
     
     
       8. An automated cassette handler as in claim 1 wherein the gripper means comprises: two pivotally mounted gripper arms coupled to the swinger housing;   a tip connected to a first end of each of said gripper arms, said tip adapted for engaging the cassette; and   a first actuator coupled to a second end of each of said gripper arms for pivoting the gripper arms.   
     
     
       9. An automated cassette handler as in claim 8 wherein the first actuator comprises: a first air cylinder having a first throw rod; and   a first spring to retract the first throw rod.   
     
     
       10. An automated cassette handler as in claim 8 wherein the tip is removable. 
     
     
       11. An automated cassette handler as in claim 8 wherein the first sensor means comprises: a gripper microswitch coupled to at least one of the gripper arms for signaling the position of the tips relative to the cassette; and   a guide microswitch coupled to the swinger housing for signaling whether a cassette is present within the gripper means.   
     
     
       12. An automated cassette handler as in claim 1 wherein the depressor means comprises: a pivotally mounted depressor arm;   a depressor bar coupled to a first end of the depressor arm for pressing against the wafers within the cassette along the open side of the cassette; and   a second actuator coupled to a second end of the depressor arm for pivoting the depressor arm.   
     
     
       13. An automated cassette handler as in claim 12 wherein the second actuator comprises: a second air cylinder having a second throw rod; and   a second spring to retract the second throw rod.   
     
     
       14. An automated cassette handleer as in claim 12 wherein the second sensor means comprises two swing microswitches coupled to the swinger housing for signaling the position of the depressor bar relative to the cassette.